Gas turbine engines utilize fuel injectors for supplying fuel to a combustor. In the combustor, the fuel and air are ignited and burned. From the combustor, the hot gaseous fluids are directed to a turbine resulting in rotation of the turbine and an output power. The spent fluid results in an exhaust emitted from the engine.
The use of fossil fuel in gas turbine engines results in combustion products within the exhaust. These combustion products consist of carbon dioxide, water vapor, oxides of nitrogen, carbon monoxide, unburned hydrocarbons, oxides of sulfur and particulates. Of these above products, carbon dioxide and water vapor are generally not considered objectionable. In most applications, governmental imposed regulations are further restricting the remainder of the species, mentioned above, emitted in the exhaust gases.
The majority of the products of combustion emitted in the exhaust can be controlled by design modifications, cleanup of exhaust gases and/or regulating the quality of fuel used. For example, particulates in the engine exhaust have been controlled either by design modifications to the combustor and fuel injectors or by removing them by traps and filters.
Thus, the design and modifications of the fuel injectors have become more complex. Furthermore, the consistency of manufacturing to insure the commonality of fuel injectors and the repeatability of emissions has become more and more important. For example, the multiplicity of parts, such as, swirlers, cooled tips, spooked gaseous components, liquid fuel passages, gaseous fuel passages, water passages, air induction passages, etc. are examples of such complex components or parts. Historically, the manufacturing of fuel injector are labor intensive. For example, most of the fuel injectors have been fabricated from many accurately machined components. The components used for making up the fuel injectors require tedious locating and placement of the individual components one with respect to another in a very precise manner. After being properly positioned, the application of a weld material and flux is required. And, the furnace brazing of the component parts to produce a finished fuel injector is completed. In many applications, several furnace brazing operations are required. As an example, three or four different brazing operation may have to be performed at different times to gradually build up the injector assembly. This process may take typically two to three week for the assembly and test after each stage of brazing.
Additionally, the quality of fuel injectors influences servicing time and costs. A higher quality of fuel injector will reduce service time resulting in reduced costs. And, a higher quality of fuel injector will make for a more efficient gas turbine engine resulting in reduced emissions.
The present invention is directed to overcome one or more of the problems as set forth above.